Marine geophysical survey systems are used to acquire data (e.g., seismic, electromagnetic) regarding Earth formations below a body of water such as a lake or ocean. The marine geophysical survey systems may use a plurality of sensor streamers which contain one or more sensors disposed proximate an outer jacket.
In some situations, one or more sensor streamers may be disconnected from the survey system, the disconnection possibly caused by failure of a coupling mechanism or in some situations the sensor streamer may be severed (e.g., by the propeller of a passing vessel). In some failure scenarios, particularly with sensor streamers filled with alcohol or oil, the sensor streamer becomes negatively buoyant, thus tending to sink. In order to avoid complete loss of the sensor streamer, an inflatable lifting bag system may trigger (i.e., a retriever system). During initial inflation each lifting bag dislodges a respective protective cover, and as the lifting bags continue to inflate the bag systems causes the sensor streamer to surface.